[PPC] G5 imac screen burn-in

Although it is normal to see what looks like burn-in at the bottom of my screen as the backlight in my display ages, I am starting to see just a slight hint of what looks like burn-in at the top and bottom of my screen where the gnome taskbars usually reside when the gdm login appears.

The G5 iMac has no built-in display brightness controls, so I have to rely on the default settings.

What I did notice was that the top and bottom gnome taskbars are at 100% white, so I changed the brightness by setting the preferences for each taskbar by right-clicking on them, and changing to a solid color and knocking the level down just a bit.

Might come in handy for anyone who uses their iMac so much that the display doesn't blank often.